Powertrain, generic (extended)

P24D8 EVAP System Pressure Sensor/Switch B Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P24D8 reports EVAP pressure sensor B reading above its valid voltage. In GM's 2023 table 23OBDG03A the canister pressure sensor fails above 4.85 V, 97 % of the reference, counted over 640 of 800 samples and treated as Type B. Mitsubishi's 2023 Outlander PHEV applies 4.1 V for 2 s to its absolute tank pressure sensor, which shows about 101 kPa at sea level when healthy. Audi's bulletin 2069531 lists P24D8 as pressure sensor 2 shorted to positive and also shows it among codes logged under a wrong label, to be tested as sensor G950. Common findings are an open sensor ground, a signal wire touching the 5 V or 12 V supply, or an internal failure. Compare P24D7 for the low side.

Likely causes

Open ground of sensor B, signal floats high
Signal wire shorted to reference or battery voltage
EVAP pressure sensor B failed

Symptoms

  • Malfunction indicator lamp on
  • EVAP readiness monitor incomplete

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–350
Time0.5–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

evap pressure sensor b

Related codes

P24D7P24D6P24D5P24D9P0453

References: gsi.ext.gm.com, mitsubishitechinfo.com, static.nhtsa.gov.